JP2003331937A - Manufacturing method of photoelectric conversion element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid dye sensitized photoelectric conversion element with excellent photoelectric conversion efficiency which can be manufactured at low cost. <P>SOLUTION: A solar cell 1A is so-called dry type solar cell disusing electrolytic solution, which comprises a first electrode 3, a second electrode 6 arranged so as to face the first electrode 3, an electron transport layer 4 laid between the first and second electrodes, a dyestuff layer D contacting with the electron transport layer 4, a hole transport layer 5 laid between the electron transport layer 4 and the second electrode 6 contacting with the dyestuff layer D, and a barrier layer 8. The above elements are formed on a base plate 2. The hole transport layer is formed by applying hole transport layer material on the dyestuff layer D by coating method, and the coating method is carried out under reduced pressure. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photoelectric conversion element.

[0002]

2. Description of the Related Art Conventionally, as an environmentally friendly power source,
Solar cells (photoelectric conversion elements) using silicon have been attracting attention. Among the solar cells that use silicon, there are single-crystal silicon type solar cells that are used in artificial satellites, etc., but as practical ones, especially solar cells that use polycrystalline silicon and amorphous silicon are used. The solar cells that have been put into practical use have begun to be used for industrial and household purposes.

However, any of these solar cells using silicon has a high manufacturing cost, requires a large amount of energy for manufacturing, and is not necessarily an energy-saving power source.

Further, Japanese Patent Laid-Open No. 01-220380,
JP 05-504023 A and JP 06-511.
The dye-sensitized wet-type solar cell as disclosed in Japanese Patent No. 113 uses an electrolytic solution having a high vapor pressure, and thus has a problem that the electrolytic solution is volatilized.

In addition, in order to make up for such drawbacks,
Presentation of complete solid-state dye-sensitized solar cell (K. Tennakone,
GRRA Kumara, IRM Kottegoda, KGU Wijiayan
tha, and VPS Perera: J. Phys. D: Appl. Phys. 31
(1998) 1492).

This solar cell has a structure having an electrode in which a TiO ₂ layer is laminated and a p-type semiconductor layer provided on the TiO ₂ layer. However, such a solar cell has a drawback that the p-type semiconductor layer penetrates the TiO ₂ layer and short-circuits with the electrode.

In this presentation, CuI is used as the constituent material of the p-type semiconductor layer. The solar cell using CuI has a problem that the generated current is lowered due to deterioration due to an increase in the crystal grains of CuI.

Further, the method of applying CuI, which is a constituent material of the p-type semiconductor layer used in this presentation, is a solution in which 0.6 g of CuI is dissolved in 20 mL of acetonitrile which is a solvent (when the insoluble matter remains, the supernatant portion is removed). Solution), Ti
A method of coating on the O ₂ layer is used.

However, in this coating method, CuI
Acetonitrile vapor used as a solvent for the solution
Since the pressure is high, T formed by CuI in a nanoporous state
iO ₂The solvent acetonitril is required before it fully penetrates the layer.
Since it will volatilize, it was formed into a nanoporous state.
TiO₂CuI does not penetrate into the layer enough
O₂There was a problem that it was deposited on the upper surface of the layer.

That is, the fact that CuI does not sufficiently penetrate into the TiO ₂ layer formed in the nanoporous state means that the TiO ₂ formed in the nanoporous state has an enormous surface area.
_This means that the contact area with the _two layers cannot be sufficiently obtained and the photoelectric conversion efficiency is not improved, and the characteristics of the dye-sensitized nanoporous structure photoelectric conversion device are not fully utilized.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state dye-sensitized photoelectric conversion device which can be manufactured at low cost and has excellent photoelectric conversion efficiency.

[0012]

The above object is achieved by the present invention described in (1) to (16) below. (1) A first electrode, a second electrode that is installed so as to face the first electrode and has a catalyst layer on its surface, and is located between the first electrode and the second electrode. , At least a part of which is positioned in contact with a porous electron transporting layer, a dye layer in contact with the electron transporting layer, and a catalyst layer formed on the surface of the electron transporting layer and the second electrode. A method for manufacturing a photoelectric conversion element having a hole transport layer, wherein the hole transport layer is formed by applying a hole transport layer material onto the dye layer by a coating method. Device manufacturing method.

(2) The method of manufacturing a photoelectric conversion element according to claim 1, wherein the coating method is performed under reduced pressure.

(3) The reduced pressure state is 13.3 Pa to 1.
33 * 10 < ^-4 > Pa (1 * 10 <-1> -1 * 10 < ^-6 > torr) The manufacturing method of the photoelectric conversion element of Claim 2 which is.

(4) The method of manufacturing a photoelectric conversion element according to claim 3, wherein the coating method is performed in a vacuum chamber.

(5) In the coating method, the amount of the hole transport material dropped onto the dye layer is 1 to 0.001 mL / min with respect to an area of 1 cm ^2. Method for manufacturing conversion element.

(6) According to the coating method, the start of dropping the hole transport material onto the dye layer is started 0.5 to 5 minutes after the reduced pressure inside the reduced pressure chamber. The method for manufacturing a photoelectric conversion element according to claim 3, wherein.

(7) The method of manufacturing a photoelectric conversion element according to claim 3, wherein the coating method is performed by subjecting the photoelectric conversion element to heat treatment.

(8) The method of manufacturing a photoelectric conversion element according to claim 3, wherein the heat treatment is performed for 5 to 60 minutes.

(9) The method of manufacturing a photoelectric conversion element according to claim 3, wherein the heat treatment is performed at a temperature of 50 to 150 ° C.

(10) The method for manufacturing a photoelectric conversion element according to claim 3, wherein in the reduced pressure state, the gas in the voids in the porous layer of the electron transport layer is removed.

(11) In the coating method, the dropping of the hole transport layer material onto the upper surface of the electron transport layer 4 on which the dye layer D is formed is performed by alternately or simultaneously performing the dropping step and the drying step. 5. The method for manufacturing the photoelectric conversion element according to 5.

(12) The hole transport layer formed by the coating method has an average thickness of 1 to 500 μm.
A method for manufacturing the photoelectric conversion element according to 1.

(13) The method of manufacturing a photoelectric conversion element according to claim 4, wherein the decompression chamber has a decompression valve and a decompression chamber.

(14) The method of manufacturing a photoelectric conversion element according to claim 4, wherein a check valve is installed at the injection port of the hole transport material in the coating method of the decompression chamber.

(15) The method of manufacturing a photoelectric conversion element according to claim 4, wherein the check valve is made of silicone rubber.

(16) A solar cell according to any one of claims 1 to 1.
5. The method for manufacturing the photoelectric conversion element according to any one of 5 above.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the photoelectric conversion device of the present invention shown in the accompanying drawings will be described in detail below.

<First Embodiment> FIG. 1 is a partial cross-sectional view showing a first embodiment when the photoelectric conversion element of the present invention is applied to a solar cell, and FIG. 2 is a thickness of the solar cell of the first embodiment. 4 is an enlarged view showing a cross section near the central portion in the vertical direction, FIG. 3 is a partially enlarged view showing a cross section of the electron transport layer in which the dye layer is formed,
FIG. 5 is a schematic diagram showing the configurations of the electron transport layer and the dye layer.
Is a schematic diagram showing the principle of the solar cell, and FIG. 6 is a diagram showing an equivalent circuit of the solar cell circuit shown in FIG.

The solar cell 1 shown in FIG. 1 is a so-called completely solid-type dye-sensitized solar cell that does not require an electrolyte solution, and is opposed to the first electrode 3 and the first electrode 3. The installed second electrode 6, the electron transport layer 4 located between them, and the dye layer D in contact with the electron transport layer 4.
And a hole transport layer 5 located between the electron transport layer 4 and the second electrode 6 and in contact with the dye layer D, and a barrier layer 8,
These are installed on the substrate 2.

Each component will be described below. In the following description, the upper surface of each layer (each member) is referred to as the “upper surface” and the lower surface is referred to as the “lower surface” in FIGS. 1 and 2.

The substrate 2 is for supporting the first electrode 3, the barrier layer 8, the electron transport layer 4, the dye layer D, the hole transport layer 5 and the second electrode 6, and is a flat member. It is composed of.

In the solar cell 1A of the present embodiment, as shown in FIG. 1, from the substrate 2 and the first electrode 3 side described later,
For example, it is used by irradiating (irradiating) with light such as sunlight (hereinafter, simply referred to as “light”). Therefore, each of the substrate 2 and the first electrode 3 is preferably substantially transparent (colorless transparent, colored transparent or translucent). Thereby, the light can efficiently reach the dye layer D described later.

The constituent material of the substrate 2 is, for example,
Various glass materials, various ceramic materials, polycarbonate (PC), polyethylene terephthalate (PET)
Examples of various resin materials such as, or various metal materials such as aluminum.

The average thickness of the substrate 2 is appropriately set depending on the material, application, etc., and is not particularly limited, but can be set as follows, for example.

When the substrate 2 is made of a hard material such as a glass material, the average thickness thereof is 0.1 to 10.
It is preferably about 1.5 mm, and 0.8 to 1.2 m
It is more preferably about m.

When the substrate 2 is made of a flexible material (flexible material) such as polyethylene terephthalate (PET), its average thickness is 0.
It is preferably about 5 to 150 μm, and 10 to 75 μm
It is more preferably about m.

The substrate 2 can be omitted if necessary.

On the upper surface of the substrate 2, a layered (plate-shaped) first
Electrode 3 is installed. In other words, the first electrode 3
Is installed on the light receiving surface side of the electron transport layer 4 on which the dye layer D described later is formed so as to cover the light receiving surface.
The first electrode 3 receives the electrons generated in the dye layer D described later via the electron transport layer 4 and the barrier layer 8,
It is transmitted to the external circuit 100 connected to this.

As the constituent material of the first electrode 3, for example, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium oxide (IO),
Metal oxides such as tin oxide (SnO ₂ ), metals such as aluminum, nickel, cobalt, platinum, silver, gold, copper, molybdenum, titanium and tantalum, or alloys containing these, or various carbons such as graphite Examples thereof include materials, and one or more of these may be used in combination.

As the average thickness of the first electrode 3, the material,
It is appropriately set depending on the application and the like, and is not particularly limited, but for example, the following can be performed.

When the first electrode 3 is composed of the above metal oxide (transparent conductive metal oxide), its average thickness is preferably about 0.05 to 5 μm, and 0.1
More preferably, it is about 1.5 μm.

When the first electrode 3 is made of the above-mentioned metals, alloys containing these, or various carbon materials, the average thickness thereof is preferably about 0.01 to 1 μm, and 0 is preferable. More preferably, it is about 0.03 to 0.1 μm.

The first electrode 3 is not limited to the one having the configuration shown in the figure, and may have a shape having a plurality of comb teeth, for example. In this case, since the light passes between the plurality of comb teeth and reaches the dye layer D, the first electrode 3 does not need to be substantially transparent. This allows
The range of selection of the constituent material of the first electrode 3 and the forming method (manufacturing method) can be expanded. Also, in this case, the first
The average thickness of the electrode 3 is not particularly limited, but is preferably about 1 to 5 μm, for example.

Further, as the first electrode 3, it is also possible to use a comb-teeth-shaped electrode like this and a transparent electrode made of ITO, FTO or the like in combination (for example, by laminating).

On the upper surface of the first electrode 3, a film-shaped (layered) barrier layer (short-circuit preventing means) 8 is provided. In addition,
Details of the barrier layer 8 will be described later.

On the upper surface of the barrier layer 8, a porous electron transport layer 4 and a dye layer D which is in contact with the electron transport layer 4 are provided.

The electron transport layer 4 has a function of transporting at least electrons generated in the dye layer D.

Examples of the constituent material of the electron transport layer 4 include titanium dioxide (TiO ₂ ) and titanium monoxide (Ti).
O), titanium oxide such as dititanium trioxide (Ti ₂ O ₃ ), n-type oxide semiconductor materials such as zinc oxide (ZnO) and tin oxide (SnO ₂ ), and other n-type semiconductor materials. Among these, one kind or a combination of two or more kinds can be used, and among these, it is preferable to use titanium oxide, particularly titanium dioxide. That is, the electron transport layer 4 is preferably composed mainly of titanium dioxide.

Titanium dioxide is particularly excellent in electron transporting ability and highly sensitive to light, so that the electron transporting layer 4 itself can generate electrons. as a result,
In the solar cell 1A, the photoelectric conversion efficiency (power generation efficiency) can be further improved.

Since the crystal structure of titanium dioxide is stable, the electron transport layer 4 mainly composed of titanium dioxide is used.
Then, even if it is exposed to a harsh environment, it has an advantage that it does not change (deteriorate) over time and stable performance can be continuously obtained for a long time.

Further, as the titanium dioxide, those having a crystal structure mainly composed of anatase type titanium dioxide, those mainly composed of rutile type titanium dioxide, and a mixture of anatase type titanium dioxide and rutile type titanium dioxide are used. It may be one of the main ones.

Titanium dioxide having an anatase type crystal structure has an advantage that electrons can be more efficiently transported.

When rutile type titanium dioxide and anatase type titanium dioxide are mixed, the mixing ratio of rutile type titanium dioxide and anatase type titanium dioxide is
Although not particularly limited, for example, 95: 5 to 5: 5 by weight ratio.
It is preferably about 95, and is 80:20 to 20:80.
It is more preferable that the degree is.

The electron transport layer 4 has a plurality of holes (pores) 41. FIG. 3 schematically shows a state where light is incident on the electron transport layer 4. As shown in FIG. 3, light passing through the barrier layer 8 (arrows in FIG. 3) is emitted by the electron transport layer 4
Of the electron transport layer 4 or is reflected in any direction in the hole 41 (diffuse reflection, diffusion, etc.). At this time, the light comes into contact with the dye layer D, and electrons and holes can be generated in the dye layer D with high frequency.

The porosity of the electron transport layer 4 is not particularly limited, but is preferably about 5 to 90%, more preferably about 15 to 50%, and more preferably 2
It is more preferably about 0 to 40%.

By setting the porosity of the electron transport layer 4 within such a range, the surface area of the electron transport layer 4 can be made sufficiently large. Therefore, the formation area (formation region) of the dye layer D (see below) formed along the outer surface of the electron transport layer 4 and the inner surface of the hole 41 can be sufficiently increased. Therefore, in the dye layer D, sufficient electrons can be generated and the electrons can be efficiently transferred to the electron transport layer 4. As a result, in the solar cell 1A, the power generation efficiency (photoelectric conversion efficiency) can be further improved.

The electron transport layer 4 may have a relatively large thickness, but a film-shaped one is preferable.
This is advantageous because the solar cell 1A can be made thinner (smaller) and the manufacturing cost can be reduced.

In this case, the average thickness (film thickness) of the electron transport layer 4 is not particularly limited, but is, for example, 0.1 to 0.1.
It is preferably about 300 μm, and 0.5 to 100 μm.
It is more preferably about m, and even more preferably about 1 to 25 μm.

The electron transport layer 4 is formed in such a manner that the dye layer D is brought into contact with the dye by, for example, adsorbing, bonding (covalent bond, coordinate bond) or the like.

The dye layer D is a light-receiving layer that generates electrons and holes by receiving light, and is formed along the outer surface of the electron transport layer 4 and the inner surface of the hole 41 as shown in FIG. . Thereby, the electrons generated in the dye layer D can be efficiently transferred to the electron transport layer 4.

The dye constituting the dye layer D is not particularly limited, but examples thereof include pigments and dyes,
These can be used alone or in combination,
It is preferable to use a pigment from the viewpoint of less deterioration and deterioration with time, and a dye from the viewpoint of more excellent adsorptivity to the electron transport layer 4 (bondability with the electron transport layer 4).

The pigment is not particularly limited, and examples thereof include phthalocyanine-based pigments such as phthalocyanine green and phthalocyanine blue, fast yellow,
Azo series such as disazo yellow, condensed azo yellow, benzimidazolone yellow, dinitroaniline orange, benzimidazolone orange, toluidine red, permanent carmine, permanent red, naphthol red, condensed azo red, benzimidazolone carmine, benzimidazolone brown Pigments, anthrapyrimidine yellow, anthraquinone pigments such as anthraquinonyl red, azomethine pigments such as copper azomethine yellow,
Quinophthalone pigments such as quinophthalone yellow, isoindoline pigments such as isoindoline yellow, nitroso pigments such as nickel dioxime yellow, perinone pigments such as perinone orange, quinacridone magenta, quinacridone maroon, quinacridone scarlet, quinacridone red, etc. Quinacridone pigments, perylene red, perylene pigments such as perylene maroon, pyrrolopyrrole pigments such as diketopyrrolopyrrole red, organic pigments such as dioxazine pigments such as dioxazine violet, carbon black, lamp black, furnace black, Carbon pigments such as ivory black, graphite and fullerene, chromate pigments such as yellow lead, molybdate orange, cadmium yellow, cadmium lithopone yellow and cadmium Sulfide, cadmium lithopone orange, silver vermillion, cadmium red, cadmium lithopone red, sulfide pigments such as sulfur, ocher, titanium yellow, titanium barium nickel yellow, red iron oxide, amber, amber iron oxide, zinc iron chrome brown , Chrome oxide, cobalt green, cobalt chrome green, titanium cobalt green, cobalt blue, cerulean blue, cobalt aluminum chrome blue, iron black, manganese ferrite black, cobalt ferrite black, copper chrome black, copper chrome manganese black, etc. Pigments, hydroxide pigments such as Viridian,
Examples include ferrocyanide pigments such as dark blue, silicate pigments such as ultramarine blue, phosphate pigments such as cobalt violet and mineral violet, and inorganic pigments such as cadmium sulfide and cadmium selenide. The
These can be used alone or in combination of two or more.

[0064] As the dye is not particularly limited, for _{example, RuL 2 (SCN) 2,} RuL 2 Cl 2, RuL 2 CN 2, Rutenium
535-bisTBA (manufactured by Solaronics), a metal complex dye such as [RuL ₂ (NCS ₂ ] ₂ H ₂ O, a cyan dye, a xanthene dye,
Azo dye, hibiscus dye, blackberry dye,
Raspberry pigments, pomegranate juice pigments, chlorophyll pigments and the like can be mentioned, and one kind or a combination of two or more kinds thereof can be used. L in the above composition formula
Represents 2,2'-bipyridine or a derivative thereof.

On the upper surface of the electron transport layer 4 on which the dye layer D is formed, a layered (plate-shaped) hole transport layer 5 is provided. In other words, the hole transport layer 5 is provided so as to face the first electrode 3 with the electron transport layer 4 having the dye layer D formed therebetween. The hole transport layer 5 has a function of capturing and transporting holes generated in the dye layer D. In other words, the hole transport layer 5 has a function of transporting holes to the external circuit 100 via the second electrode 6 described later, or the hole transport layer 5 itself serves as an electrode.

The average thickness of the hole transport layer 5 is not particularly limited, but is preferably about 1 to 500 μm, more preferably about 10 to 300 μm, and more preferably about 10 to 30 μm. Is more preferable.

Examples of the constituent material of the hole transport layer 5 include substances having various ion-conducting properties, triphenyldiamine (monomers, polymers, etc.), polyaniline, polypyrrole, polythiophene, phthalocyanine compounds (eg, copper phthalocyanine), or these. Examples thereof include various p-type semiconductor materials such as derivatives of Al, nickel, cobalt, platinum, silver, gold, copper, molybdenum, titanium, tantalum, and alloys containing these. One kind or a combination of two or more kinds can be used, and in particular, a substance having ionic conductivity is preferably used. That is, the hole transport layer 5 is preferably composed mainly of a substance having ionic conductivity. Thereby, the hole transport layer 5 is
The holes generated in the dye layer D can be transported more efficiently.

Examples of the substance having this ion-conducting property include metal iodide compounds such as CuI and AgI, metal halide compounds such as metal bromide compounds such as AgBr, and metal thiocyanate such as CuSCN. Examples thereof include salts (metal rhodanide compounds) and the like, and these can be used alone or in combination of two or more.

Among these, metal halide compounds such as metal iodide compounds and metal bromide compounds are preferable as the substance having ionic conductivity. The metal halide compound is particularly excellent in ionic conductivity.

Further, as the substance having ionic conductivity, it is particularly preferable to use one kind or a combination of two or more kinds of metal iodide compounds such as CuI and AgI. The metal iodide compound has extremely excellent ionic conductivity. Therefore, by using the metal iodide compound as the main material of the hole transport layer 5, the solar cell 1
The photoelectric conversion efficiency (energy conversion efficiency) of A can be further improved.

As shown in FIG. 2, the hole transport layer 5 is formed by penetrating into the holes 41 of the electron transport layer 4 in which the dye layer D is formed. As a result, the contact area between the dye layer D and the hole transport layer 5 can be increased, so that holes generated in the dye layer D can be more efficiently transferred to the hole transport layer 5. it can. As a result, the solar cell 1A can further improve the power generation efficiency.

On the upper surface of the hole transport layer 5, a layered (plate-shaped) layer is formed.
Second electrode 6 is installed.

The average thickness of the second electrode 6 is
It is appropriately set depending on the application and the like and is not particularly limited.

As the constituent material of the second electrode 6,
For example, aluminum, nickel, cobalt, platinum,
Examples thereof include metals such as silver, gold, copper, molybdenum, titanium, and tantalum, alloys containing these, and various carbon materials such as graphite. One or two of these are included.
A combination of two or more species can be used.

Further, since the photoelectric conversion element of the present invention is a photochemical element, an interface is formed between the second electrode 6 and the hole transport layer 5, and a catalyst layer is formed on this interface. There is.

In the conventional dye-sensitized wet photoelectric conversion device, since the electrolyte solution composed of iodine solution or the like is used for the hole transport layer, the gap between the second electrode 6 and the electron transport layer 4 which adsorbs the dye is used. In this structure, a gap having a certain distance is formed by using a spacer or the like, and this gap has a structure in which an electrolyte solution which is a hole transport layer is filled.

Such conventional dye-sensitized wet solar cells, K. Tennakone, GRRA Kumara, IRM Kottegoda,
KGU Wijiayantha, and VPS Perera: J. Phys. D:
Appl. Phys. 31 (1998) 1492, etc., discloses a conventional solid-state dye-sensitized solar cell, etc., in which a substrate on which a second electrode is formed and an electron transport layer 4 on which a dye is adsorbed are formed. The hole transporting layer and the second electrode are pressed against each other by sandwiching them with the clipped substrate and physically contacted by the pressing, and there is a problem that the contact resistance is large. .

However, in the completely solid type dye-sensitized photoelectric conversion element of the present invention, an interface is formed between the second electrode 6 and the hole transport layer 5, and a catalyst layer is formed at this interface. This is different from the conventional dye-sensitized solar cell described above.

The interface level of the interface between the hole transport layer 5 and the catalyst layer of the solid-state dye-sensitized photoelectric conversion element of the present invention is preferably 0.1 to 0.0001 eV,
A more preferable interface state is 0.01 to 0.001 eV.

In the present invention, the catalyst layer is formed on the hole transport layer 5 by spin coating, printing, spray coating,
A wet process such as coating is used to form an interface between the hole transport layer 5 and the catalyst layer. In the subsequent process of these wet processes (wet process), the catalyst layer may be dried and baked.

Further, in the present invention, the catalyst layer on the hole transport layer 5 is formed by a dry process (dry method) such as sputtering, vapor deposition, CVD method, etc. An interface is formed between and.

As the catalyst layer, Pt (platinum), Pt-R
Although u (platinum-ruthenium), Au (gold), etc. are used, various carbon materials such as graphite are optimal in the present invention.

As an example of the carbon material, one or more of graphite, graphite, diamond, carbon nanotube, fullerene (C60) and the like are used.

Carbon fibers may be woven into these carbon materials in order to increase the strength of the carbon materials. As the carbon fibers, there are used organic fibers such as rayon and polyacrylonitrile, and fibers produced by spinning refined petroleum pitch by heat treatment in an inert gas and carbonizing.

Particularly, the carbon fiber made of polyacrylonitrile has high elasticity and high strength, and the composite agent obtained by solidifying the carbon fiber with the above-mentioned carbon material and resin is most suitable as the catalyst layer of the present invention.

The carbon fiber and the resin have conductivity.

Furthermore, it is necessary to form the hole transport layer more smoothly in order to form a more closely adhered interface between the second electrode 6 and the hole transport layer 5.

It is desirable that the surface of the hole transport layer on the side of the interface with the catalyst layer is flat, and the surface roughness of the surface of the hole transport layer on the side of the interface with the catalyst layer is Rmax (maximum surface roughness). ) Is preferably 10 μm or less, and Ra (average surface roughness) is preferably 5 μm or less.

The surface roughness of the formed catalyst layer is also R
It is desirable that max (maximum surface roughness) is 10 μm or less, and Ra (average surface roughness) is 5 μm or less.

In such a solar cell 1A, as shown in FIG. 5, when light is incident, electrons are excited mainly in the dye layer D to generate electrons (e ⁻ ) and holes (h ⁺ ). To do.
Among these, the electrons move to the electron transport layer 4 and the holes move to the hole transport layer 5, and between the first electrode 3 and the second electrode 6,
A potential difference (photoelectromotive force) is generated, and a current (photoexcitation current) flows in the external circuit 100.

The value of Vaccum Energy shown in FIG.
This is an example in which the electron transport layer 4 and the barrier layer 8 are made of titanium dioxide, and the hole transport layer 5 is made of CuI.

If this state is represented by an equivalent circuit, a current circulating circuit having a diode 200 as shown in FIG. 6 is formed.

By irradiating light (receiving light), the dye layer D
In the following, electrons and holes are generated at the same time, but in the following description, it is described as “electrons are generated” for convenience.

The present invention is characterized in that short-circuit preventing means for preventing or suppressing a short circuit (leakage) between the first electrode 3 and the hole transport layer 5 is provided.

The short-circuit preventing means will be described in detail below.

In the present embodiment, a barrier layer 8 having a film shape (layer shape) and located between the first electrode 3 and the electron transport layer 4 is provided as a short circuit preventing means. The barrier layer 8 is formed so that its porosity is smaller than that of the electron transport layer 4.

When manufacturing the solar cell 1A, as described later, for example, a hole transport layer material is applied to the upper surface of the electron transport layer 4 on which the dye layer D is formed, by a coating method. .

In this case, in a solar cell in which the barrier layer 8 is not provided, if the porosity of the electron transport layer 4 is increased, the hole transport layer material becomes a hole of the electron transport layer 4 in which the dye layer D is formed. It may penetrate into the inside 41 and reach the first electrode 3. That is, in the solar cell having no barrier layer 8, the leakage current increases due to the contact (short circuit) between the first electrode 3 and the hole transport layer 5, and the power generation efficiency (photoelectric conversion efficiency) is increased. May be reduced.

On the other hand, in the solar cell 1A provided with the barrier layer 8, the inconvenience as described above is prevented, and the decrease in power generation efficiency is suitably prevented or suppressed.

When the porosity of the barrier layer 8 is A [%] and the porosity of the electron transport layer 4 is B [%], B /
A is, for example, preferably about 1.1 or more, 5
It is more preferably about 10 or more, and even more preferably about 10 or more. Thereby, the barrier layer 8 and the electron transport layer 4 can exhibit their respective functions more suitably.

More specifically, the porosity A of the barrier layer 8 is preferably about 20% or less,
It is more preferably about 5% or less, further preferably about 2% or less. That is, the barrier layer 8 is preferably a dense layer. Thereby, the effect can be further improved.

Further, the thickness ratio of the barrier layer 8 and the electron transport layer 4 is not particularly limited, but is, for example, 1:99 to.
It is preferably about 60:40 and 10:90 to 4
It is more preferably about 0:60. In other words, the ratio of the thickness of the barrier layer 8 to the whole of the barrier layer 8 and the electron transport layer 4 is preferably about 1 to 60%, more preferably about 10 to 40%. Accordingly, the barrier layer 8 can more reliably prevent or suppress a short circuit due to contact between the first electrode 3 and the hole transport layer 5, and at the same time, the light arrival rate to the dye layer D is reduced. This can be suitably prevented.

More specifically, the average thickness (film thickness) of the barrier layer 8 is, for example, preferably about 0.01 to 10 μm, more preferably about 0.1 to 5 μm, More preferably, it is about 0.5 to 2 μm. Thereby, the effect can be further improved.

The constituent material of the barrier layer 8 is not particularly limited. For example, in addition to titanium oxide, which is the main constituent material of the electron transport layer 4, for example, SrTiO ₃ , Zn.
Various metal oxides such as O, SiO ₂ , Al ₂ O ₃ and SnO ₂ , CdS, CdSe, TiC, Si ₃ N ₄ , SiC, B
It is possible to use one kind or a combination of two or more kinds of various metal compounds such as ₄ N and BN, and among them, those having electric conductivity equivalent to that of the electron transport layer 4 are preferable, and particularly, Those mainly containing titanium oxide are more preferable. By forming the barrier layer 8 with such a material, the electrons generated in the dye layer D can be more efficiently transferred from the electron transport layer 4 to the barrier layer 8, and as a result, the power generation efficiency of the solar cell 1A. Can be further improved.

The resistance values in the thickness direction of the barrier layer 8 and the electron transport layer 4 are not particularly limited, but the resistance values in the thickness direction of the entire barrier layer 8 and the electron transport layer 4, that is, the barrier value. The resistance value in the thickness direction of the layered product of the layer 8 and the electron transport layer 4 is preferably about 100 Ω / cm ² or more, more preferably about 1 kΩ / cm ² or more. Thereby, it is possible to more reliably prevent or suppress a leak (short circuit) between the first electrode 3 and the hole transport layer 5, and it is possible to prevent a decrease in power generation efficiency of the solar cell 1A. There is.

The interface between the barrier layer 8 and the electron transport layer 4 may or may not be clear, but it is preferably not clear (unclear). That is, it is preferable that the barrier layer 8 and the electron transport layer 4 are integrally formed and partially overlap each other. This makes it possible to transfer electrons more reliably (efficiently) between the barrier layer 8 and the electron transport layer 4.

Further, the barrier layer 8 and the electron transport layer 4 are
A structure in which materials having the same composition (for example, a material mainly containing titanium dioxide) is used, and only the porosities thereof are different, that is, a part of the electron transport layer 4 is part of the barrier layer 8 is formed.
May be configured to function as.

In this case, the electron transport layer 4 has a dense portion and a rough portion in the thickness direction, and the dense portion functions as the barrier layer 8.

In this case, it is preferable that the dense portion is formed on the electron transport layer 4 on the first electrode 3 side.
It can also be formed at any position in the thickness direction.

Further, in this case, the electron transport layer 4 has a structure having a portion sandwiching a rough portion between dense portions, or a structure having a portion sandwiching a dense portion between rough portions. It may be.

In such a solar cell 1A, the dye layer D
The photoelectric conversion efficiency when the incident angle of light on the (electron transport layer 4 on which the dye layer D is formed) is 90 ° is R _90, and the incident angle of light is 5
When the photoelectric conversion efficiency at 2 ° is R ₅₂ , it is preferable that R ₅₂ / R ₉₀ has a property of about 0.8 or more, and more preferably about 0.85 or more. . Satisfying such a condition means that the electron transport layer 4 on which the dye layer D is formed has a low directivity to light, that is,
It is isotropic. Therefore, such a solar cell 1A can generate power more efficiently over almost the entire sunshine duration of the sun.

Further, in the solar cell 1A, the first electrode 3
Is positive and the second electrode 6 (hole transport layer 5) is negative, and when a voltage of 0.5 V is applied, its resistance value is
For example, it preferably has a characteristic of about 100 Ω / cm ² or more, and more preferably has a characteristic of about 1 kΩ / cm ² or more. Having such characteristics indicates that, in the solar cell 1A, a short circuit (leakage) due to contact or the like between the first electrode 3 and the hole transport layer 5 is preferably prevented or suppressed. It is a thing. Therefore,
In such a solar cell 1A, the power generation efficiency (photoelectric conversion efficiency) can be further improved.

Such a solar cell 1A can be manufactured, for example, as follows.

First, the substrate 2 made of soda glass or the like is prepared. As the substrate 2, a substrate having a uniform thickness and no bending is preferably used.

<1> First, the first electrode 3 is formed on the upper surface of the substrate 2. The first electrode 3 can be formed by using, for example, the material of the first electrode 3 composed of FTO or the like by using, for example, a vapor deposition method, a sputtering method, a printing method or the like.

<2> Next, the barrier layer 8 is formed on the first electrode 3
Formed on the upper surface of. The barrier layer 8 may be formed by, for example, a sol-gel method, a vapor deposition (vacuum vapor deposition) method, a sputtering method (high frequency sputtering, DC sputtering), a spray pyrolysis method, a jet mold (plasma spraying) method, a CVD method, or the like. Of these, it is preferable to form them by the sol-gel method.

This sol-gel method is extremely easy to operate. For example, by using it in combination with various coating methods such as dipping, dropping, doctor blade, spin coating, brush coating, spray coating and roll coater, The barrier layer 8 can be preferably formed in a film shape (thick film and thin film) without requiring a large-scale device.

Further, according to the coating method, the barrier layer 8 having a desired pattern shape can be easily obtained by masking using, for example, a mask.

The sol-gel method does not allow (prevent) a reaction (for example, hydrolysis, polycondensation, etc.) of a titanium compound (organic or inorganic) described later in the barrier layer material (hereinafter referred to as " MOD (Metal Organic Deposition
Or "Metal Organic Decomposition) method". ), Or a method which allows this, but it is particularly preferable to use the MOD method.

According to this MOD method, the stability of the titanium compound (organic or inorganic) in the barrier layer material is maintained, and the barrier layer 8 is more easily and surely (reproducibly) and dense. (Porosity within the above range).

Particularly, titanium tetraisopropoxide (T
PT), titanium tetramethoxide, titanium tetraethoxide, titanium tetrabutoxide, and the like, using an organic titanium compound such as titanium alkoxide (metal alkoxide) which is chemically extremely unstable (easy to decompose)
When forming an iO ₂ layer (barrier layer 8 of the present invention),
This MOD method is optimal.

The method of forming the barrier layer 8 by the MOD method will be described below.

[Preparation of Barrier Layer Material] For example, among organic titanium compounds such as titanium alkoxide (metal alkoxide) such as titanium tetraisopropoxide (TPT), titanium tetramethoxide, titanium tetraethoxide, and titanium tetrabutoxide. In the case of using one kind or a combination of two or more kinds, first, this organic titanium compound (or this solution) is treated with, for example, anhydrous ethanol,
It is dissolved in an organic solvent (or a mixed solvent thereof) such as 2-butanol, 2-propanol, and 2-n-butoxyethanol.

Thereby, the concentration (content) of the organic titanium compound in the solution is adjusted (for example, 0.1 to 10 mol).
/ L) to adjust the viscosity of the resulting barrier layer material. The viscosity of the barrier layer material is appropriately set depending on the type of the coating method and the like, and is not particularly limited, but when spin coating is used, it is preferably high viscosity (for example, about 0.5 to 20 cP (normal temperature)). When a spray coat is used, it is preferable that the viscosity is low (for example, 0.1
Approximately 2 cP (normal temperature)).

Next, to this solution, for example, titanium tetrachloride, acetic acid, acetylacetone, triethanolamine,
An additive having a function of stabilizing the titanium alkoxide (metal alkoxide) such as diethanolamine is added.

By adding these additives, these additives substitute for the alkoxide (alkoxyl group) coordinated with the titanium atom in the titanium alkoxide and coordinate with the titanium atom. This suppresses the hydrolysis of the titanium alkoxide and stabilizes it. That is, these additives function as a hydrolysis inhibitor that suppresses the hydrolysis of the titanium alkoxide. in this case,
The compounding ratio of this additive to the titanium alkoxide is not particularly limited, but for example, it is preferable that the molar ratio is about 1: 2 to 8: 1.

More specifically, when diethanolamine is coordinated to the titanium alkoxide, it replaces (substitutes) the alkoxide (alkoxyl group) of the titanium alkoxide, and two molecules of diethanolamine coordinate to the titanium atom. The compound substituted with this diethanolamine becomes a more stable compound in producing titanium dioxide than titanium alkoxide.

The same applies to combinations in other cases.

As a result, a barrier layer material (barrier layer forming sol liquid: MOD sol liquid) is obtained.

When an inorganic titanium compound such as titanium tetrachloride (TTC) is used, this inorganic titanium compound (or its solution) is treated with absolute ethanol, 2-butanol, 2-propanol, 2-n-butoxyethanol. When dissolved in an organic solvent such as (or a mixed solvent thereof), the organic solvent coordinates with titanium and becomes a stable compound without adding an additive.

Further, when an organic titanium compound such as titanium oxyacetylacetonate (TOA) is used,
Since this organic titanium compound (or this solution) is stable alone, a stable barrier layer material can be obtained by dissolving it in the organic solvent.

In the present invention, when the barrier layer 8 is formed by the MOD method, among the above-mentioned three solutions,
It is optimum to use a solution prepared by the following method. That is, titanium tetraisopropoxide (TP
T), an organic titanium compound such as titanium tetramethoxide, titanium tetraethoxide, titanium alkoxide such as titanium tetrabutoxide (or a solution thereof) is dissolved (or diluted) with a solvent, and titanium tetrachloride and acetic acid are added to the solution. It is optimum to use a solution prepared by a method of adding additives such as acetylacetone, triethanolamine, diethanolamine and the like. According to this method, it is possible to obtain a compound that is stabilized when titanium dioxide is produced by coordinating the additive with the titanium atom of the titanium alkoxide.

As a result, the chemically unstable titanium alkoxide can be made into a chemically stable compound. Such a compound is extremely useful in forming the barrier layer 8 of the present embodiment, that is, the dense barrier layer 8 containing titanium dioxide as a main material.

[Formation of Barrier Layer 8] A barrier layer material is applied to the upper surface of the first electrode 3 by a coating method (for example, spin coating) to form a film. When spin coating is used as the coating method, the rotation speed is 500 to 4000 rpm.
It is preferably carried out to the extent.

Then, heat treatment is applied to the coating film. Thereby, the organic solvent is volatilized and removed. The heat treatment condition is preferably about 50 to 250 ° C.
It is about 60 minutes, more preferably about 100 to 200 ° C. and about 5 to 30 minutes.

Such heat treatment can be carried out, for example, in air or nitrogen gas, or in addition to various inert gases,
Vacuum and depressurized state [eg, 13.3 Pa to 1.33 × 10 ^-4
It may be performed in a non-oxidizing atmosphere such as Pa (1 × 10 ^-1 to 1 × 10 ^-6 Torr).

The coating of the barrier layer material on the upper surface of the first electrode 3 may be carried out while heating the first electrode 3.

Further, the coating film is heat-treated at a temperature higher than the above heat treatment. As a result, the organic component remaining in the coating film is removed, and titanium dioxide (TiO ₂ ) is sintered to form the barrier layer 8 made of titanium dioxide having an amorphous or anatase type crystal structure. The heat treatment conditions are preferably about 300 to 700 ° C. for about 1 to 70 minutes, more preferably about 400 to 550 ° C. for about 5 to 45 minutes.

The atmosphere of the heat treatment can be the same as that of the heat treatment.

The above operation is preferably carried out in the range of 1 to 20.
The barrier layer 8 having an average thickness as described above is formed about once, more preferably about 1 to 10 times.

In this case, the thickness (film thickness) of the coating film obtained by one operation described above is preferably about 100 nm or less, and more preferably about 50 nm or less.
By forming the barrier layer 8 by laminating such thin films, the barrier layer 8 can be made more uniform and dense. Further, the adjustment of the film thickness obtained by the above-described operation can be easily performed by adjusting the viscosity of the barrier layer material.

Prior to the formation of the barrier layer 8, the first
The upper surface of the electrode 3 of, for example, O ₂ plasma treatment, EB
The organic substance attached to the upper surface of the first electrode 3 may be removed by performing a treatment, a cleaning treatment with an organic solvent (for example, ethanol, acetone, or the like). in this case,
A mask layer is formed on the upper surface of the first electrode 3 and masked in advance, leaving a portion for forming the barrier layer 8. Further, the mask layer may be removed after the barrier layer 8 is formed, or may be removed after the solar cell 1A is completed.

<3> Next, the electron transport layer 4 is formed on the upper surface of the barrier layer 8. The electron transport layer 4 is, for example, sol
It can be formed by a gel method, a vapor deposition method, a sputtering method or the like, and among them, the sol-gel method is preferable.

This sol-gel method is extremely easy to operate. For example, by using it in combination with various coating methods such as dipping, dropping, doctor blade, spin coating, brush coating, spray coating, and roll coater, The electron transport layer 4 is preferably used without requiring a large-scale device.
Can be formed into a film (thick film and thin film).

In addition, according to the coating method, the electron transport layer 4 having a desired pattern can be easily obtained by masking using a mask or the like.

For forming the electron transport layer 4, it is preferable to use a sol liquid containing a powder of the electron transport layer material. Thereby, the electron transport layer 4 can be made porous more easily and reliably.

The average particle size of the powder of the electron transport layer material is not particularly limited, but is preferably about 1 nm to 1 μm, more preferably about 5 to 50 nm. By setting the average particle size of the powder of the electron transport layer material within the above range, it is possible to improve the uniformity of the powder of the electron transport layer material in the sol liquid. Further, since the surface area (specific surface area) of the obtained electron transport layer 4 can be increased by reducing the average particle size of the powder of the electron transport layer material in this way, the formation region (formation of the dye layer D) Area) can be made larger, and solar cell 1
It contributes to the improvement of power generation efficiency of A.

An example of the method for forming the electron transport layer 4 will be described below.

[Preparation of Titanium Oxide Powder (Powder for Electron Transport Layer Material)] <3-A0> A rutile-type titanium dioxide powder and an anatase-type titanium dioxide powder are mixed at a predetermined mixing ratio (only anatase-type titanium dioxide powder is used). , And rutile type titanium dioxide powder alone).

The average particle size of these rutile type titanium dioxide powders and the average particle size of the anatase type titanium dioxide powders may be different or the same, but they are different. Is preferred.

The average particle size of the titanium oxide powder as a whole is within the above range.

[Preparation of Sol Solution (Electron Transport Layer Material)] <3-A1> First, for example, titanium such as titanium tetraisopropoxide (TPT), titanium tetramethoxide, titanium tetraethoxide and titanium tetrabutoxide. Organic titanium compounds such as alkoxide and titanium oxyacetylacetonate (TOA), and titanium tetrachloride (T
TC) and the like, one or a combination of two or more of inorganic titanium compounds, for example, anhydrous ethanol, 2-
It is dissolved in an organic solvent (or a mixed solvent thereof) such as butanol, 2-propanol and 2-n-butoxyethanol.

At this time, the concentration (content) of the titanium compound (organic or inorganic) in the solution is not particularly limited, but is preferably about 0.1 to 3 mol / L, for example.

Next, if necessary, various additives are added to this solution. When titanium alkoxide, for example, is used as the organic titanium compound, titanium alkoxide has low chemical stability, and therefore, additives such as acetic acid, acetylacetone and nitric acid are added. Thereby, the titanium alkoxide can be made into a chemically stable compound. In this case, the compounding ratio of this additive and the titanium alkoxide is not particularly limited, but, for example,
The molar ratio is preferably about 1: 2 to 8: 1.

<3-A2> Next, water such as distilled water, ultrapure water, ion-exchanged water, or RO water is mixed with this solution. The mixing ratio of this water and the titanium compound (organic or inorganic) is preferably about 1: 4 to 4: 1 in terms of molar ratio.

<3-A3> Then, the titanium oxide powder prepared in the step <3-A0> is mixed with the solution to obtain a suspension (dispersion) liquid.

<3-A4> Further, this suspension is diluted with the above-mentioned organic solvent (or mixed solvent). This prepares a sol liquid. The dilution ratio is preferably about 1.2 to 3.5 times, for example.

The content of the titanium oxide powder (electron transport layer material powder) in the sol solution is not particularly limited, but is preferably about 0.1 to 10 wt% (wt%), More preferably, it is about 0.5 to 5 wt%. Thereby, the porosity of the electron transport layer 4 can be preferably set within the above range.

[Formation of Electron Transport Layer (Titanium Oxide Layer) 4] <3-A5> While the barrier layer 8 is preferably heated, the barrier layer 8 is coated on the upper surface thereof by a coating method (for example, dropping).
The sol solution is applied to obtain a film-like body (coating film). The heating temperature is not particularly limited, but is, for example, 80 to 180.
The temperature is preferably about 0 ° C, more preferably about 100 to 160 ° C.

The above operation is preferably carried out in the range of 1 to 10
The electron transport layer 4 having the above-mentioned average thickness is formed about once, more preferably about 5 to 7 times.

Next, the electron transport layer 4 may be subjected to heat treatment (for example, firing) at a temperature of about 250 to 500 ° C. for about 0.5 to 3 hours, if necessary.

<3-A6> The electron transport layer 4 obtained in the step <3-A5> can be subjected to a post-treatment, if necessary.

As the post-processing, for example, mechanical processing (post-processing) such as grinding and polishing for adjusting the shape.
Other examples include post-treatment such as cleaning and chemical treatment.

The electron transport layer 4 can also be formed as follows, for example. Hereinafter, another method of forming the electron transport layer 4 will be described. In the following explanation,
The description will focus on the differences from the above-described forming method, and the description of the same items will be omitted.

[Preparation of Titanium Oxide Powder (Powder for Electron Transport Layer Material)] <3-B0> The same step as the above step <3-A0> is performed.

[Preparation of Coating Liquid (Electron Transport Layer Material)] <3-B1> First, the titanium oxide powder prepared in the above step is mixed with an appropriate amount of water (for example, distilled water, ultrapure water, ion-exchanged water, RO). Suspended in water).

<3-B2> Next, a stabilizer such as nitric acid is added to the suspension and sufficiently kneaded in a mortar made of agate (or made of alumina).

<3-B3> Then, in the suspension,
The above water is added and the mixture is further kneaded. At this time, the compounding ratio of the stabilizer and water is preferably 10:90 by volume.
~ 40: 60, more preferably 15: 85-30:
The viscosity of the suspension is, for example, 0.2 to
It is about 30 cP (normal temperature).

<3-B4> Then, in the suspension,
For example, a surfactant is added and kneaded so that the final concentration is about 0.01 to 5 wt%. Thus, the coating liquid (electron transport layer material) is prepared.

The surfactant is a cationic,
It may be anionic, zwitterionic or nonionic, but nonionic ones are preferably used.

Further, as the stabilizer, instead of nitric acid,
It is also possible to use a titanium oxide surface modification reagent such as acetic acid or acetylacetone.

In the coating solution (electron transport layer material),
If necessary, various additives such as a binder such as polyethylene glycol, a plasticizer and an antioxidant may be added.

[Formation of Electron Transport Layer (Titanium Oxide Layer) 4] <3-B5> A coating liquid is applied and dried on the upper surface of the first electrode 3 by a coating method (for example, dipping) to form a film. Form the body (coating). Alternatively, the coating and drying operations may be performed a plurality of times to stack the layers. This allows
The electron transport layer 4 is obtained.

Then, the electron transport layer 4 may be subjected to heat treatment (eg, firing) at a temperature of about 250 to 500 ° C. for about 0.5 to 3 hours, if necessary. As a result, the titanium oxide powders that have just stopped contacting each other are diffused at the contact portions, and the titanium oxide powders are fixed (fixed) to some extent. In this state, the electron transport layer 4 becomes porous.

<3-B6> The same step as the step <3-A6> is performed. The electron transport layer 4 is obtained through the above steps.

<4> Next, the electron transport layer 4 and a liquid containing the dye as described above (for example, a solution in which the dye is dissolved in a solvent, a suspension in which the dye is suspended in the solvent) are immersed, for example. , Dyes D are formed on the outer surface of the electron transport layer 4 and the inner surfaces of the holes 41 by, for example, adsorbing, bonding, and the like.

More specifically, the substrate 2, the first electrode 3,
The dye layer D can be easily formed along the outer surface of the electron transport layer 4 and the inner surface of the hole 41 by immersing the laminate of the barrier layer 8 and the electron transport layer 4 in the liquid containing the dye.

The solvent (liquid) that dissolves or suspends (disperses) the dye is not particularly limited, and examples thereof include various types of water, methanol, ethanol, isopropyl alcohol, acetonitrile, ethyl acetate, ether, methylene chloride, NMP (N). -Methyl-2-pyrrolidone) and the like, and one or more of them can be used in combination.

After that, the laminated body is treated with the solution (suspension).
From the inside, the solvent is removed by, for example, a method of natural drying or a method of blowing a gas such as air or nitrogen gas.

If necessary, the laminate may be dried in a clean oven or the like at a temperature of about 60 to 100 ° C. for about 0.5 to 2 hours. Thereby, the dye can be more strongly adsorbed (bonded) to the electron transport layer 4.

<5> Next, the hole transport layer 5 is formed on the upper surface of the dye layer D (the electron transport layer 4 on which the dye layer D is formed).

For the hole transport layer 5, for example, a hole transport layer material (electrode material) containing a substance having an ion conductive property such as CuI is provided on the upper surface of the electron transport layer 4 on which the dye layer D is formed.
For example, it is preferably formed by coating by various coating methods such as dipping, dropping, doctor blade, spin coating, brush coating, spray coating and roll coater.

According to such a coating method, the hole transport layer 5
Can be more surely permeated into the holes 41 of the electron transport layer 4 in which the dye layer D is formed.

In addition, in these coating methods, the above-mentioned dye layer D is put in a state where the substrate 2 having the dye layer D formed on the electron transport layer 4 is put in a container at least depressurized from the atmospheric pressure. It is desirable that the hole transport layer 5 be applied to the upper surface of the above by various coating methods described above.

More specifically, the decompression chamber shown in FIG. 7 is used. As shown in FIG. 7, the decompression chamber includes, for example, an upper structure 80 and a lower structure 79,
Positioning is performed by the positioning port 76 and the positioning pin 77, and the upper structure and the lower structure are caulked with a sealing member 81 made of silicon rubber or the like with nuts and bolts so as to be in close contact with each other.

This decompression chamber has a suction port 78, a decompression valve (valve) 74, and a decompression chamber 75, and the suction port 78 is connected to a vacuum pump. When the vacuum pump is operated with the pressure reducing valve (valve) 74 opened, the pressure in the pressure reducing chamber 75 is reduced, and as described above, 1 × 10 ⁻¹ to 1 × 10.
A vacuum state of about ^-6 torr is achieved.

The dye layer D is placed in the closed chamber.
The substrate 2 formed on the electron transport layer 4 is put into the chamber, and the pressure in the chamber is reduced. Then, the silicone rubber provided on the substrate 2 of the chamber is pierced with the needle 71 of the syringe 73 containing the hole transport material, and the dye layer formed on the electron transport layer 4 in a state where the airtight state is not broken. The hole transport material in the syringe is slowly dropped onto D and applied.

At this time, the amount of the hole transport material dropped onto the substrate was 1 to 0.001 mL per 1 cm ² area.
Every minute.

According to the coating method, the dropping of the hole transport material onto the dye layer is started 1 to 5 minutes after the pressure in the pressure reducing chamber is reduced.

As described above, when the hole transport layer is coated on the substrate 2 on which the dye layer D is formed on the electron transport layer 4, if the coating process is performed under reduced pressure, the electron transport layer is formed in the electron transport layer. The air (gas) in the voids in the formed porous layer can be degassed.

Therefore, the penetration of CuI into the TiO ₂ layer formed in the nanoporous state can be further assisted.

At this time, the depressurized state is lower than the atmospheric pressure, but more specifically, 13.3 Pa to
It is preferably 1.33 × 10 ⁻⁴ Pa (1 × 10 ⁻¹ to 1 × 10 ⁻⁶ torr), and more preferably 13.3 Pa or more.
1.33 × 10 ^-1 Pa ^- it is more desirable that ^{(1 × 10 1 ~1 × 10} -3 torr).

The average thickness of the hole transport layer 5 formed by the coating method is not particularly limited, but for example,
It is preferably about 1 to 500 μm, and 10 to 300
The thickness is more preferably about μm, further preferably about 10 to 30 μm.

Thereafter, the needle 71 of the syringe 73 containing the hole transport material is placed in the check valve 72 made of silicon rubber or the like provided on the substrate 2 placed in the decompression chamber 75 of the chamber.
The hole transporting material in the syringe 71 is slowly dropped and applied onto the dye layer D formed on the electron transporting layer 4 in a state where the airtight state of the vacuum chamber is not broken.

Further, after the coating film is formed, the coating film may be heat-treated, but the dye layer D of the hole transport layer material may be used.
Coating on the upper surface of the electron transport layer 4 on which the
It is preferable to perform it while heating (the electron transport layer 4 on which the dye layer D is formed). As a result, the hole transport layer 5 can be more quickly formed.
Is advantageous in shortening the manufacturing time of the solar cell 1A.

The heating temperature is preferably 5
The temperature is set to about 0 to 150 ° C., and this heat treatment is performed for 5 to 60 minutes. When heat treatment is performed after forming the coating film,
The coating film may be dried before such heat treatment.

The above operation may be repeated a plurality of times.

More specifically, the substrate 2, the first electrode 3, the barrier layer 8 are placed on a hot plate heated to about 80 ° C.
And the laminated body of the electron transport layer 4 on which the dye layer D is formed is installed, and the hole transport layer material is dropped on the upper surface of the electron transport layer 4 on which the dye layer D is formed, and dried. This operation is repeated a plurality of times to form the hole transport layer 5 having the above-mentioned average thickness.

As described above, when the hole transport material is applied under reduced pressure using the vacuum chamber, 8
The decompression chamber is installed on a hot plate heated to about 0 ° C., and a coating process is performed.

The solvent used for the hole transport layer material is not particularly limited, but for example, organic solvents such as acetonitrile, ethanol, methanol, isopropyl alcohol, etc., or one kind or a combination of two or more kinds such as various kinds of water are used. be able to.

Acetonitrile is preferably used as a solvent for dissolving a substance having ionic conductivity.

At this time, in the present invention, as the solution of the hole transport layer material, a low-concentration CuI solution prepared by dissolving 200 to 1 mg of the hole transport material in 10 mL of the solvent is used.

More preferably, the hole transport layer material solution is a low-concentration CuI solution prepared by dissolving 100 to 10 mg of the hole transport material in 10 mL of the solvent.

For example, when acetonitrile is used as the solvent, a low-concentration CuI solution in which 2.5 to 0.05% by weight of CuI is dissolved in 10 mL (7.8 g) of acetonitrile is used.

More preferably, acetonitrile 10 m
A low-concentration CuI solution having CuI dissolved in a weight ratio of 1.5 to 0.1% with respect to L (7.8 g) is used.

More specifically, 10 mL of acetonitrile
(7.8g), 100mg (weight ratio 1.28)
%) CuI is used to dissolve CuI in a low concentration.

This coating method is based on this low concentration CuI.
The solution is permeated onto the dye layer in 2 to 100 times and applied, and the low-concentration CuI solution is applied at intervals of low-concentration Cu.
After the solvent of the solution I is volatilized or immediately before volatilization, the solution is continuously applied.

As described above, in the present invention, since the CuI solution having a low concentration is used, the amount of CuI in one coating step can be reduced. Therefore, the volatilization of acetonitrile causes CuI to form an upper surface of the TiO ₂ layer. It is possible to solve the problem of depositing on the surface.

Further, as in the present invention, the low-concentration CuI solution is continuously applied a plurality of times (about 2 to 100 times), so that the solvent, acetonitrile, can re-apply CuI deposited on the upper surface of the TiO ₂ layer. It is possible to assist the penetration of CuI into the TiO ₂ layer that is dissolved and formed into a nanoporous state.

Further, when a low-concentration CuI solution is used as in the present invention, the amount of solvent in a unit solution can be increased, so that the time for volatilization of the solvent acetonitrile can be lengthened.

Further, in the present invention, a cyanoethylated compound such as cyanoresin may be added as a binder to the acetonitrile solution of the substance having the ionic conductivity. In this case, the cyanoethylated compound is added to the substance having the ionic conductivity in a mass ratio (weight ratio) of 5
It is preferable to mix (blend) at 0.5 wt%.

The hole transport layer material preferably contains a hole transport efficiency improving substance having a function of improving hole transport efficiency. When the hole transport layer material contains this hole transport efficiency improving substance, the hole transport layer 5 has a higher carrier mobility due to the improvement of the ionic conductivity. As a result, the hole transport layer 5 has improved electrical conductivity.

The hole transport efficiency improving substance is not particularly limited, but examples thereof include halides such as ammonium halides, and particularly ammonium halides such as tetrapropylammonium iodide (TPAI) are preferably used. . As a substance that improves hole transport efficiency,
By using an ammonium halide, especially tetrapropylammonium iodide, the hole transport layer 5
The carrier mobility is further increased by further improving the ion conduction characteristics. As a result, the hole transport layer 5
Further improves its electrical conductivity.

The content of the hole transport efficiency improving substance in the hole transport layer material is not particularly limited, but is 1 × 10 ⁻⁴ to 1
It is preferable that it is about × 10 ⁻¹ wt% (weight%).
More preferably, it is in the range of x10 ^-4 to 1 x 10 ^-2 wt%. Within such a numerical range, the above-mentioned effect becomes more remarkable.

When the hole transport layer 5 is composed mainly of a substance having an ionic conduction characteristic, the hole transport layer material is a crystal of a substance having an ionic conduction characteristic when crystallized. It is preferable to contain a crystal size coarsening suppressing substance that suppresses an increase in size.

As the crystal size coarsening suppressing substance,
Although not particularly limited, examples thereof include thiocyanate (rhodanide) and the like in addition to the above-mentioned cyanoethylated compound, hole transport efficiency improving substance. Further, the crystal size coarsening suppressing substance may be used alone or in combination of two or more.

As the thiocyanate, for example,
Sodium thiocyanate (NaSCN), potassium thiocyanate (KSCN), copper thiocyanate (CuSC
N), ammonium thiocyanate (NH ₄ SCN) and the like.

Further, as a crystal size coarsening suppressing substance,
When a hole transport efficiency improving substance is used, ammonium halide is suitable. Among the hole transport efficiency improving substances, ammonium halide is particularly excellent in the function of suppressing the increase in the crystal size of the substance having the ion conductive property.

If the hole transport layer material does not contain this crystal size coarsening suppressing substance, depending on the type of substance having ionic conduction characteristics, the above-mentioned heating temperature, etc.
When a substance having ion-conducting properties is crystallized, the crystal size may become too large, and the volume expansion of the crystal may proceed excessively. In particular, when such crystallization occurs in the holes (small holes) of the barrier layer 8, cracks are generated in the barrier layer 8 and, as a result, between the hole transport layer 5 and the first electrode 3,
A short circuit may occur partially due to contact or the like.

Further, when the crystal size of the substance having the ionic conduction property increases, the electron transport layer 4 in which the dye layer D is formed may be formed depending on the kind of the substance having the ionic conduction property.
There is a case where the contact property with is lowered. As a result, the substance having the ionic conductivity, that is, the hole transport layer 5 may be separated from the electron transport layer 4 on which the dye layer D is formed.

Therefore, such a solar cell may deteriorate in device characteristics such as photoelectric conversion efficiency.

On the other hand, when the hole transport layer material contains the crystal size coarsening inhibiting substance, the substance having the ionic conduction property suppresses the increase of the crystal size and the crystal size becomes extremely small or small. It will be small.

For example, when thiocyanate is added to a solution of CuI in acetonitrile, thiocyanate ions (SCN ⁻ ) are adsorbed around Cu atoms in CuI dissolved in a saturated state, and Cu—S ( Sulfur)
Bonding occurs. As a result, C dissolved in a saturated state
The binding between uI molecules is significantly inhibited, resulting in C
Since it is possible to prevent the crystal growth of uI, it is possible to obtain a CuI crystal grown finely.

From the above, the solar cell 1A can suitably suppress the inconvenience caused by the coarsening of the crystal size of the substance having the ion conduction characteristic as described above.

The content of the crystal size coarsening suppressing substance in the hole transport layer material is not particularly limited, but is preferably about 1 × 10 ^{6 to} 10 wt% (weight%). More preferably, it is about 10 ⁻⁴ to 1 × 10 ⁻² wt%. Within such a numerical range, the above-mentioned effect becomes more remarkable.

Further, the hole transport layer 5 is formed of p as described above.
In the case of using a p-type semiconductor material, the p-type semiconductor material may be, for example, acetone or isopropyl alcohol (IP
A) A hole transport layer material is prepared by dissolving (or suspending) it in various organic solvents (or mixed solvents containing these) such as ethanol. Using this hole transport layer material, the hole transport layer 5 is formed (formed) in the same manner as described above.

<6> Next, the second electrode 6 is formed on the upper surface of the hole transport layer 5. The second electrode 6 is formed by using, for example, a vapor deposition method using the material of the second electrode 6 made of platinum or the like.
It can be formed by using a sputtering method, a printing method, or the like.

<7> Next, the photoelectric conversion element sandwiched between the first electrode and the second electrode 6 is plasticized by heat or light.

This treatment is a treatment for more firmly associating the hole transporting layer made of CuI with the TiO ₂ layer having the plastic binder (conductive resin) and the dye adsorbed thereon, and further for making the mixture fit.

That is, by plasticizing the plastic binder (conductive resin) contained in the hole transport layer made of CuI or the like, the hole transport layer is sufficiently permeated into the TiO ₂ layer formed in the nanoporous state, Make them adhere closely.

The viscosity (20 ° C.) of the plastic binder (conductive resin) used at this time is 150 to 7000 cP, and the appearance is granular or viscous, and more preferably the plastic binder ( The viscosity (20 ° C.) of the conductive resin is particularly preferably 240 to 1200 cP.

The softening temperature of the plastic binder (conductive resin) is 25 to 200 ° C., and more preferably, the softening temperature of the plastic binder (conductive resin) is 40 to 120 ° C. It is particularly suitable.

The softening temperature of the plastic binder (conductive resin) needs to be such that the dye adsorbed by the heat of plasticizing the binder is not destroyed. Regarding the plastic treatment method of the contained plastic binder (conductive resin),
This will be specifically described.

The first plasticizing method is thermoplastic processing. This thermoplastic treatment is performed at a temperature of 25 to 250 ° C. and is continued for a time of about 5 to 300 minutes.

The second plasticizing treatment is photoplasticizing treatment. This photo-plasticizing treatment is carried out with a halogen or xenon light source, and is continued at a temperature of 25 to 250 ° C. for a time of about 5 to 300 minutes.

Through the above steps, the solar cell 1A is manufactured.

Although the photoelectric conversion element of the present invention has been described above based on the illustrated embodiments, the present invention is not limited to these. Each part constituting the photoelectric conversion element,
It can be replaced with an arbitrary one having the same function.

The photoelectric conversion element of the present invention may be a combination of any two or more configurations of the first and second embodiments.

The photoelectric conversion element of the present invention is applicable not only to solar cells but also to various elements (light receiving elements) such as optical sensors and optical switches that receive light and convert it into electric energy. Is something that can be done.

Further, in the photoelectric conversion element of the present invention, the incident direction of light may be from the opposite direction, unlike the one shown in the drawing. That is, the incident direction of light is arbitrary.

[0241]

EXAMPLES Next, specific examples of the present invention will be described.

Example 1 The solar cell (photoelectric conversion element) shown in FIG. 1 was manufactured as follows.

-0- First, the size: length 30 mm x width 35
A soda glass substrate having a size of mm × thickness of 1.0 mm was prepared.
Next, this soda glass substrate was immersed in a cleaning liquid (mixed liquid of sulfuric acid and hydrogen peroxide solution) at 85 ° C. for cleaning to clean the surface.

-1- The FTO electrode (first electrode) having dimensions of 30 mm in length × 35 mm in width × 1 μm in thickness was formed on the upper surface of the soda glass substrate by vapor deposition.

-2- Next, a barrier layer was formed in a region of 30 mm in length × 30 mm in width on the upper surface of the formed FTO electrode. This was done as follows.

[Preparation of Barrier Layer Material] First, titanium tetraisopropoxide (organic titanium compound) was added to 2-n-
It was dissolved in butoxyethanol to a concentration of 0.5 mol / L.

Then, diethanolamine (additive) was added to this solution. The mixing ratio of diethanolamine and titanium tetraisopropoxide was set to 2: 1 (molar ratio).

As a result, a barrier layer material was obtained. In addition,
The barrier layer material had a viscosity of 3 cP (normal temperature).

[Formation of Barrier Layer] The barrier layer material was applied by spin coating (coating method) to obtain a coating film. The spin coating was performed at a rotation speed of 1500 rpm.

Then, the laminated body of the soda glass substrate, the FTO electrode and the coating film was placed on a hot plate and
The coating film was dried by heat treatment at 60 ° C. for 10 minutes.

[0251] Further, the laminate was heated at 480 ° C for 30 minutes.
The organic components remaining in the coating film were removed by applying a heat treatment in the oven for 1 minute.

The above operation was repeated 10 times so that the layers were laminated.

Thus, a barrier layer having a porosity of less than 1% was obtained. The average thickness of this barrier layer is 0.9 μm.
Met.

-3- Next, a titanium oxide layer (electron transport layer) was formed on the upper surface (entire surface) of the barrier layer. This was done as follows.

[Preparation of Titanium Oxide Powder] Titanium oxide powder made of a mixture of rutile type titanium dioxide powder and anatase type titanium dioxide powder was prepared. The average particle size of the titanium oxide powder was 40 nm, and the compounding ratio of the rutile type titanium dioxide powder and the anatase type titanium dioxide powder was 60:40 by weight.

[Preparation of Sol Solution (Titanium Oxide Layer Material)] First, titanium tetraisopropoxide was dissolved in 2-propanol to a concentration of 1 mol / L.

Next, acetic acid (additive) was added to this solution,
Mix with distilled water. The mixing ratio of acetic acid and titanium tetraisopropoxide is 1: 1 (molar ratio), and the mixing ratio of distilled water and titanium tetraisopropoxide is 1: 1 (molar ratio). So that

Next, the prepared titanium oxide powder was mixed with this solution. Further, this suspension was diluted 2-fold with 2-propanol. Thus, a sol liquid (titanium oxide layer material) was prepared.

The content of titanium oxide powder in the sol solution was set to 3 wt%.

[Formation of Titanium Oxide Layer] A soda glass substrate, FTO electrode and barrier layer laminate were placed on a hot plate heated to 140 ° C., and a sol solution (titanium oxide layer material) was placed on the upper surface of the barrier layer. Is dropped (application method),
Dried. This operation was repeated 7 times so that the layers were laminated.

As a result, a titanium oxide layer having a porosity of 34% was obtained. The average thickness of this titanium oxide layer was 7.
It was 2 μm.

The resistance value in the thickness direction of the entire barrier layer and titanium oxide layer was 1 kΩ / cm ₂ or more.

-4- Next, soda glass substrate, FT
The laminated body of the O electrode, the barrier layer and the titanium oxide layer was immersed in a saturated ethanol solution of ruthenium trisbipidyl (organic dye), and then taken out from the ethanol solution.
Ethanol was volatilized by natural drying. Furthermore, 80
After drying in a clean oven at 0 ° C. for 0.5 hours, it was left overnight. As a result, a dye layer was formed along the outer surface of the titanium oxide layer and the inner surface of the holes.

-5-Next, soda glass substrate, FT
In the state where at least the laminate of the titanium oxide layer on which the O electrode, the barrier layer and the dye layer D are formed is placed in the decompression chamber shown in FIG.
The hole transport layer 5 is applied to the upper surface of the above by various coating methods described above.

More specifically, the substrate 2 having the dye layer D formed on the electron transport layer 4 is placed in the closed chamber shown in FIG. 7, and this chamber is depressurized.

Next, the decompression valve (valve) 7 of the decompression chamber
With the No. 4 open, operate the vacuum pump, and
The inside of 5 is evacuated to a vacuum of about 1 × 10 ^-2 torr.

After that, the syringe 73 in which the hole transport material is put in the silicon rubber provided on the substrate 2 of the chamber
The needle 71 is pierced and the hole transporting material in the syringe is slowly dropped and applied onto the dye layer D formed on the electron transporting layer 4 in a state where the airtight state is not broken.

At this time, the amount of the hole transport material dropped onto the substrate is 0.01 mL / min for an area of 1 cm ² .

According to the coating method, the dropping of the hole transport material onto the dye layer was started 1 to 5 minutes after the pressure in the pressure reducing chamber was reduced.

The average thickness of the hole transport layer 5 formed by the coating method was about 20 μm.

The decompression chamber was placed on a hot plate heated to 80 ° C., an acetonitrile solution of CuI (hole transport layer material) was dropped on the upper surface of the titanium oxide layer on which the dye layer D was formed, and dried. I went while.

This operation was repeated about 2 to 100 times so that the CuI solution formed into a nanoporous state TiO ₂
A CuI layer (hole transport layer) having dimensions of 30 mm in length × 30 mm in width × 20 μm in thickness was formed so as to sufficiently penetrate the layer.

In the acetonitrile solution, tetrapropylammonium iodide was added as a hole transport efficiency improving substance so as to be 1 × 10 ⁻³ wt%.

In addition, CuI was added to the acetonitrile solution.
As a binder of, cyanoresin (cyanoethylated product) was added. In addition, CuI and cyanoresin were mixed in a mass ratio (weight ratio) of 97: 3.

Further, sodium thiocyanate (NaSCN) was added to the acetonitrile solution as a crystal size coarsening inhibiting substance so as to have a concentration of 1 × 10 ⁻³ wt%.

-6- Then, on the upper surface of the CuI layer, dimensions: 30 mm in length × 30 mm in width × 0.1 in thickness by vapor deposition.
mm platinum electrode (second electrode) was formed.

-7- Next, the photoelectric conversion element sandwiched between the first electrode and the second electrode 6 was photo-annealed with a xenon light source. At this time, the temperature is 110 ° C. and the time is 180 minutes. Made at the temperature of.

[0278]

As described above, according to the present invention, in the photoelectric conversion element sandwiched by the first electrode and the second electrode 6, the hole transport layer is made of the hole transport layer material. It is formed by coating on the dye layer by a coating method, and since the coating method is performed in a reduced pressure state, there is little deterioration of the photoelectric conversion element, and there is an effect that the photoelectric conversion efficiency is improved. .

The photoelectric conversion element of the present invention is easy to manufacture and can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a first embodiment when a photoelectric conversion element of the present invention is applied to a solar cell.

FIG. 2 is an enlarged view showing a cross section in the vicinity of a central portion in the thickness direction of the solar cell of the first embodiment.

FIG. 3 is a partially enlarged view showing a cross section of an electron transport layer on which a dye layer is formed.

FIG. 4 is a schematic diagram showing a configuration of an electron transport layer and a dye layer.

FIG. 5 is a schematic diagram showing the principle of a solar cell.

6 is a diagram showing an equivalent circuit of the solar cell circuit shown in FIG.

FIG. 7 is a diagram showing an example of the present invention.

[Explanation of symbols]

1A, 1B ... Solar cell 2 ... Substrate 3 ... First electrode 4 ... Electron transport layer 41 ... Hole 5 ... Hole transport layer 51 ... Convex portion 6 ...
Second electrode 7 ... Spacer 8 ... Barrier layer 11A
…… Layered body 12A …… Layered body 11B …… Layered body 1
2B: laminated body 100: external circuit 200: diode D: dye layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsutomu Miyamoto             Seiko, 3-3-3 Yamato, Suwa City, Nagano Prefecture             -In Epson Corporation F-term (reference) 5F051 AA14                 5H032 AA06 AS06 AS16 BB02 BB05                       BB10 EE04 EE16 EE18 HH00                       HH04 HH06

Claims (16)

[Claims] 1. A first electrode, a second electrode that is installed so as to face the first electrode and has a catalyst layer on its surface, and between the first electrode and the second electrode. Located at least partly in contact with the electron transport layer, a dye layer in contact with the electron transport layer, and a catalyst layer formed on the surface of the electron transport layer and the second electrode. A method of manufacturing a photoelectric conversion element having a hole transport layer comprising: the hole transport layer, wherein the hole transport layer is formed by applying a hole transport layer material onto the dye layer by a coating method. A method for manufacturing a photoelectric conversion element, comprising: 2. The method for manufacturing a photoelectric conversion element according to claim 1, wherein the coating method is performed under a reduced pressure. 3. The reduced pressure state is 13.3 Pa to 1.33.
The method for producing a photoelectric conversion element according to claim 2, wherein the method is × 10 ^-4 Pa (1 × 10 ^-1 to 1 × 10 ^-6 torr). 4. The method for manufacturing a photoelectric conversion element according to claim 3, wherein the coating method is performed in a vacuum chamber. 5. The amount of the hole transport material dropped onto the dye layer in the coating method is 1 cm ² with respect to an area of 1 cm ^2.
The method for producing a photoelectric conversion element according to claim 3, wherein the photoelectric conversion element has a flow rate of about 0.001 mL / min. 6. According to the coating method, the start of dropping the hole transport material onto the dye layer is started after 0.5 to 5 minutes have elapsed after the inside of the decompression chamber was in a decompressed state. The method for manufacturing a photoelectric conversion element according to claim 3, wherein 7. The method of manufacturing a photoelectric conversion element according to claim 3, wherein the coating method is performed by subjecting the photoelectric conversion element to heat treatment. 8. The method for manufacturing a photoelectric conversion element according to claim 3, wherein the heat treatment is performed for 5 to 60 minutes. 9. The method for manufacturing a photoelectric conversion element according to claim 3, wherein the heat treatment is performed at a temperature of 50 to 150 ° C. 10. The method of manufacturing a photoelectric conversion element according to claim 3, wherein in the reduced pressure state, the gas in the void in the porous layer of the electron transport layer is degassed. 11. The dropping of the hole transport layer material in the coating method onto the upper surface of the electron transport layer 4 on which the dye layer D is formed is performed alternately or simultaneously with the dropping step and the drying step. A method for manufacturing the described photoelectric conversion element. 12. The method of manufacturing a photoelectric conversion element according to claim 3, wherein the hole transport layer formed by the coating method has an average thickness of 1 to 500 μm. 13. The method of manufacturing a photoelectric conversion element according to claim 4, wherein the decompression chamber has a decompression valve and a decompression chamber. 14. The method for manufacturing a photoelectric conversion element according to claim 4, wherein a check valve is installed at an injection port of the hole transport material in the coating method of the decompression chamber. 15. The method of manufacturing a photoelectric conversion element according to claim 4, wherein the check valve is made of silicone rubber. 16. The method for manufacturing a photoelectric conversion element according to claim 1, which is a solar cell.